In the art of feeding documents, it is known to use a separator wheel assembly in a document feeder for separating and feeding individual sheets from a stack of sheets. One type of separator, known as an interference type separator includes a separator wheel which operates in cooperation with a separator stone extending through the feed deck for performing the separating task. Generally, in an interference type separator, the separator wheel includes a plurality of angular grooves into which a plurality of inclined raised members, commonly referred to as fingers, of the separator stone protrude. The documents are fed through the bite between the separator wheel and the separator stone with the fingers of the stone operating in cooperation with the grooves in the feed roller. An example of such an interference type separator is shown in U.S. Pat. No. 4,501,417, issued Feb. 26, 1985 to Dean H. Foster and assigned to the assignee of the present invention.
The nature of separator assemblies, and in the particular with the interference type separator, is that an adjustment must be made to the spaced relationship or "bite" between the separator wheel and the separator stone whenever there is a change in documents to be fed. Typically, the bite between the separator wheel and the separator stone is adjustable for the purpose of feeding documents of various thicknesses. The adjustment once made is locked into place until documents of other thicknesses are to be fed.
Generally, when a paper jam occurs at the separator assembly, the jam cannot be cleared without some damage to the jammed sheet. The most reliable way for clearing jams at the separator assembly is through the feed path downstream from the separator assembly. However, in many instances this may require the removal of a machine cover over the downstream feed path, and may require reaching into the rollers and belts in the feed path to retrieve the jammed sheet. Even in this instance, the sheet may be damaged because of the interference relationship of the stone fingers and the separator wheel.
As previously stated, the interference type separator assembly has an adjustment which is locked into one position for feeding the particular documents being fed at that time. Currently, there is no device that would perform the singulating feeding of sheets which can also be used to feed multiple sheets without requiring a new adjustment for subsequent documents as originally fed.
In U.S. Pat. No. 4,775,140 issued Oct. 4, 1988 to Dean H. Foster and assigned to the assignee of the present invention, there is shown an envelope feeder including a second frame assembly which can be pivotally raised to provide access for clearing a jam. However, this feeder is a gap type feeder which does not require the sensitive adjustment typically required in interference type feeders. After the jam is cleared, the second frame is returned to its original position. The feeding operation is interrupted while the second frame is in the raised position.